Cable connector assembly

ABSTRACT

A cable connector assembly for minerally insulated electric cables and comprising a cable plug disposed at the cable end and a socket adapted to receive the cable plug. The cable plug is composed of contact members and of insulators disposed in consecutive aligned relationship and being of cylindrical shape, the outside diameter thereof corresponding in size to the cable diameter. The socket comprises contact elements separated by insulating discs provided with a common passage extending therethrough which is adapted to receive the cable plug.

United States Patent Hatschek et al.

[ Nov. 13, 1973 CABLE CONNECTOR ASSEMBLY Inventor: Rudolf A. Hatschek, Fribourg,

Switzerland Vibro-Meter AG, Fribourg, Switzerland Filed: Dec. 22, 1972Appl. No.: 317,550

Related US. Application Data Continuation of Ser. No. 193,607, Oct. 28,1971, abandoned.

Assignee:

US. Cl ..310/7l,310/8.4,339/182 R, 339/182 RS, 183

Int. Cl. ..I-10lr 17/18 Field of Search 310/71, 8.3; 339/182 R, 339/182RS, 183

References Cited UNITED STATES PATENTS Wilson 339/183 X 779,098 l/1905Raymond 339/183 X 3,234,500 2/1966 Buckland 339/182 R 3,289,149 11/1966Pawloski 1 339/183 3,291,926 12/1966 Nelson 339/182 RS Primgg'Examiner-J. D. Miller AssistantExaminer-Mark O. Budd AttorneyGeorge J.Netter [5 7] ABSTRACT A cable connector assembly for minerally insulatedelectric cables and comprising a cable plug disposed at the cable endand a socket adapted to receive the cable plug. The cableplug iscomposed of contact members and of insulators disposed in consecutivealigned relationship and being of cylindrical shape, the outsidediameter thereof corresponding in size to the cable diameter. The socketcomprises contact elements separated by insulating discs provided with acommon passage extending therethrough which is adapted to receive thecable plug.

8 Claims, 3 Drawing Figures PATENTED NOV 1 3 I973 SHEET 10F 2 W Hk CABLECONNECTOR ASSEMBLY This is a continuation of US. Pat. application Ser.No. 193,607, filed Oct. 28, 1971, now abandoned.

The invention relates to a cable connector assembly adapted to be usedfor connecting to equipment or interco'nnecting minerally insulatedelectric cables having two conductors which are embedded in an inorganicinsulating material and which are surrounded by a metal tube, moreparticularly for measuring and control systems comprising thermocouples,piezoelectric signal generators or pick-ups or the like. The cableconnector assembly comprising a cable plug disposed at the cable endand'a socket adapted to receive the cable plug.

A frequent requirement in the electric measuring and control art is totransmit signals from pick-ups or signal generators which are mounted inrelatively hot zones or through high-temperature areas. Minerallyinsulated cables have accordingly been devised in which the steelconductors are embedded in an inorganic insulating material, generallymagnesium oxide, enclosed by a steel tube. Cables of this kind toleratetemperatures up to above 1,000 C. One important job for which suchcables are used is to supervise aircraft engines, in particular they areused in the vibration monitoring systems of rotating engine parts bymeans of piezoelectric accelerometers and for temperature supervision bymeans of thermocouples in a fire alarm system or for function checks.The pick-ups not just the thermocouples but the vibration pick-ups tooare required to be placed inside the engine very near the parts to besupervised, so that detailed information from any disturbances which mayoccur is available and diagnosis is greatly simplified, since it isimmediately apparent which particular engine component is causingabnormal vibrations, or the exact place where there is overheating. 7 i

A main difficulty in assembling pick-ups or signal generators inside anengine is the laying of the cable. The places where the pick-ups areactually disposed are usually not very hot since bearings, gearboxes andso on are oil lubricated and thus cooled. However, the cables usuallyhave to extend through zones inside. the engine where there is sprayingoil; also, they often have to pass through stationary engine parts ontheir way to the outside surface of the engine. This is why minerallyinsulated cables are preferred, for they can withstand hightemperatures, have good mechanical strength and are of relatively smalldiameter something like 1.6 to 3.5 mm. For example, thin minerallyinsulated cables must be used where a signal line, as is usually thecase, inside a stator blade leads to the outside of the engine, sincestator blades are fairly thin and so any passages in them for cablesmust be relatively narrow.

There are therefore special difficulties in connecting cables to signalpick-ups and in interconnecting cable conductors. Since conventionalcable plugs are usually of much greater diameter than the cable, theplugs can be fitted to the cable ends only after the laying of thecable. However, the cable ends of minerally insulated cables must behermetically sealed since the inorganic insulant is hygroscopic and itsdielectric coefficient would drop undesirably if it absorbed mositure,yet it is virtually impossible to thoroughly heat, evacuate andhermetically seal cables already assembled in an engine.

It is an object of this invention to obviate these diffculties by theprovision of an adequately heat-resistant cable connector assembly forminerally insulated cables, which assembly comprises a cable plugproviding a hermetic closure of the cable end and which can be fittedthereto before the cable is assembled in the engine without making cableassembly more difficult.

According to the invention the cable plug comprises two substantiallycylindrical ceramic insulators and two tubular contact members whoseoutside diameters correspond at least substantially to the metal tubesize of the minerally insulated cable, the two tubular contact membersbeing disposed in consecutive aligned relationship so that the firstinsulator follows the metal tube of the cable, the first contact memberengages like a sleeve or nipple or the like over the two insulators andthe second contact member is engaged like a cap on the outside end ofthe second insulator, the insulators being metallized on their surfacesin contact with the metal tube and with the contact members and beinghermetically secured thereto by brazing. The socket for receiving theplug element according to the invention comprises at least twoconsecutive contact elements which are separated from one another byinsulating discs and through which at least one common passage extends.Spring liners or the like are inserted into the contact elements andcooperate with the contact members of the cable plug which is adapted tobe plugged into the common passage and ensure satisfactory electricalcontact.

Pin-like plug elements of relatively small diameter are used in radioand telecommunications, in the form of a contact pin which is connectedto an electrical conductor and which has a widened head, a sleeve madeof an insulant, as a rule plastics, being drawn on to the pin shank andbearing a sleeve-like contact element connected on its outside. to thesecond conductor. A plug casing whose dimensions greatly exceed cablediameter is needed to provide a strong connection between the plugelement and the cable sheath or covering. Also, a conventional plugelement of this kind cannot provide hermetic sealing of the cable end,nor is its ability to withstand heat sufficient for use in conditions ofsevere thermal stressing.

The cable plug according to the invention, on the other hand, forms ahermetically tight cable end piece whose diameter is little, if at all,greater than cable diameter and which is in a strong mechanicalconnection with the metal covering of the cable. Cable assembly istherefore facilitated even though the passages for the cable are narrow.Since a hermetic closure can be provided by the cable plug according tothe invention before assembling the cable in the engine, there is noneed to dry out and evacuate the cable in the place of assembly. Also,although of simple construction, the ability of the cable plug accordingto the invention to withstand high temperatures is the same as that ofminerally insulated cable. The socket of the cable connector assemblyaccording to the invention is of simple design and advantageouslyadapted to receive the cable plug. With three contact elements disposedone after another in this fashion, not only do the cable conductors haveprovision for electrical connection but the metal covering or sheath ofthe minerally insulated cable has provision for connection as screening.A socket of this kind can be disposed on or in the casing of theassociated signal generator; it is particularly suitable for providing aconductive connection between two pieces of cable, e.g. between aminerally insulated cable disposed in an engine to be monitored and aconventional cable extending from the outside of the engine.

The insulating members of the cable plug according to the invention can,with advantage, be identical; preferably, the insulators are formed withaxial passages through which the conductors extend, one conductor beingsecured to a place on the inside surface of the contact member betweenthe two insulators, the other conductor extending through a centralpassage of the cap-like end contact member and being hermeticallysecured to the outside thereof by brazing or welding. In thisconstruction it is a fairly simple job to beat out the cable end and toevacuate through the axial passages in the insulating members andthrough the central passage of the cap-like contact member before thesecond conductor is welded to the outside of the cap-like contact memberto close the central passage hermetically. Also, the insulators can bereduced on those of their surfaces withwhich they contact the metalcovering of the cable and the contact members, so that the contactmembers can be wholly or partly recessed in the insulating members andthe cable plug has a relatively smooth outside surface.

Conveniently, if the cable plug according to the invention is to be usedfor thermocouple lines, the contact members are made of the samematerial as the cable conductors, to obviate the formation of extrathermocouples at the contact zones. 1

The common passage provided in the contact elements of the socket mayextend through the insulating discs separating the contact elements. Ifthe common passage in the insulating discs is smaller than the outsidediameter of the spring means preferably formed by radially resilientcontact sleeves inserted into the common passage, the sleeves arereliably anchored in the passages of the contact elements.

In a preferred embodiment of the invention advantageously suitable forconnecting a minerally insulated cable to piezoelectric signalgenerators, in particular to piezoelectric accelerometers, the socketadapted to receive the cable plug is formed by the piezoelectric signalgenerator itself having piezoelectric crystal discs separated byelectrodes. In this embodiment, the electrodes of the signal generatorare used as the contact elements of the socket, the crystal discsforming the insulating discs. With this construction, the minerallyinsulated cable can be connected to the signal generator, just by meansof a single central passage in the piezoelement itself, thus renderingthe provision of a separate socket unnecessary.

The invention is explained in more detail below with reference to theaccompanying drawings, in which:

FIG. 1 shows, by way of example, a view in axial section of a cable plugaccording to the invention connected to a cable end;

FIG. 2 shows a view in longitudinal section of a socket or box forinterconnecting two cables, and

preferably steel, covering or sheath 5 which also forms the electricalscreening of cable 1. Sheath 5 is followed by a cylindrical insulatingmember 6 of a ceramic material, for example aluminum-oxide ceramic, anda second and identical insulating member 7 is disposed in alignment withmember 6. Between the two members 6 and 7 is a first contact member 8which is tubular and which acts as a connecting nipple between the twoinsulating members 6, 7. A cap-like second contact member 9 is disposedon the outwards end of the insulating member 7. The two insulatingmembers 6, 7 have axil passages 10, 11 through which the conductors 2, 3extend. Between the two insulating members 6, 7 the conductor 2 issecured to a place, 12 of the inside surface of contact member 8 bybrazing or welding, but conductor 3 extends through axial passage 11 ininsulating member 7 and terminates in a central passage 13 of contactmember 9. A weld connection 14 secures conductor 3 to the outside ofmember 9 and closes passage 13 hermetically.

The outside diameter of all the integers 6-9 is no greater than theoutside diameter of cable sheath 5. The cable plug is therefore nothicker than cable 1 and therefore does not cause any difficulties incable assembly. In the embodiment shown theinsulating members 6,7 arereduced or stepped at their ends to receive the components followingthem, so that the cable plug has a substantially smooth outside surface.The cable plug components and the integers 6-9 are hermetically sealedtogether by brazing, as is the insulating member 6 to sheath 5. Anadhesive metal layer is applied to boundary surfaces 15 in FlG. l tometallise the insulating members 6,7. One possible way of providing themetallising is to sinter molybdenum at a high temperature on the surfaceof the members 6,7, whereafter the sintered layer is consolidated byelectro-nickel-plating. The resulting brazed bond is mechanically strongand sealing-tight and can withstand temperatures of more than 800 C.

The weld 14 on the outside of the contact member 9 is the last item tobe formed when the cable plug is assembled. Before welding, the cable 1and the inside of the otherwise finished cable plug is first thoroughlyheated to remove moisture, then evacuated via the central passage 13 incontact member 9, then filled with an inert gas, for example helium or ahelium-nitrogen mixture. After the gas filling the conductor 3 is weldedto contact member 9 by means of the weld 14, the cable plug andtherefore the cable end being sealed hermetically. The cable plug canthen be tested for hermeticity in a mass spectrometer, conveniently withthe helium serving as indicator.

The minerally insulated cable 1 can have a cable plug according to theinvention at both its ends and thus be hermetically sealed. It is asimple matter to assemble such a cable, one of its ends being connectedto a signal pick-up such as a piezoelectric accelerometer or athermocouple while its other end is connected to an appropriate socketor box of a signal line which is connected for example outside theengine to be monitored. Alternatively the minerally insulated cable canhave one end permanently connected to signal generator or thermocouple,in which event a cable plug according to the invention is required onlyfor its other end. When such a system is assembled, for example insidean engine, signal generator or thermocouple is fitted first, whereafterthe cable is led through the various passages to the outside. The job oflaying the cable in this way is facilitated by the narrowness of thecable plug according to the invention and the factthat the same isfirmly connected to the cable sheath, the plug element'not beingconnected in this case to the signal generator or thermocouple.

FIGS. 2 and 3 show two different ways of connecting the cable plug ofFIG. 1. The embodiment shown in FIG. 2 is of a connecting socket or boxwhich can be disposed for example on the outside of an engine casing.The socket or box comprises two metal contact elements 16,17 which aresecured in casing 19 of the socket by a metal screw 18 serving ascontact member for the steel covering or sheath 5 of cable 1. Oneinsulating disc 20 each, conveniently of ceramic, is disposed betweenthe contact elements 16,17 and the screw 18, and at the end of contactelement 16 is another insulating disc 21 which bears via a plate spring22 on an end wall of casing 19. The spring 22 serves to compensate forany inequalities in heat expansion between the components of the box orsocket and to ensure that the contact elements 16,17 fit withoutclearance inside the casing 19.

A common passage 23 extends through all the integers 1620 and is adaptedto receive a cable plug secured to the end of cable 1. A resilientsleeve 24 is disposed in each contact member 16,17 and in the screw 18.The members 24 provide electrical contact between the contact membersl6,l7 and the contact members 8,9 of the cable plug and between screw 18and cable sheath 5. Socket apertures 25 are provided laterally on thetwo contact elements 16,17 and receive spring liners or sleeves or thelike 26, to receive plug pins 27 disposed at the-end of a conventionalcable 28 screwed by means of a locknut 29 to a cylindrical plugextension 30 secured to casing 19.

Screw 18 has on its outside an O-ring 31 which serves to seal the box orsocket and, if necessary, to secure the cable.

A minerally insulated cable could be connected at this place to the boxor socket instead of the conventional cable 28, in which event therequisite contact elements for receiving a cable plug according to theinvention in the plug extension 30 could be disposed in very much thesame way as in the casing 19. Alternatively, the contact elements can bedisposed in consecutive and aligned relationship to one another so thatthe ends of two cables can be interconnected coaxially. Anotheradvantageous possibility is for the same contact elements to have twopassages disposed in parallel adjacent relationship to one another andto have the requisite spring sleeves or liners or the like, in whichevent two pieces of cable can be inserted into the two passages eitherparallel and beside one another in the same direction or in oppositedirections and thus be joined together.

In the construction shown in FIG. 3, a minerally insulated cable 1having at its end a cable plug of the kind shown in FIG. 1 is pluggeddirectly into a piezoelectric accelerometer comprising a casing 32 inwhich a baseplate 33 having a prestressing sleeve 34 is secured, aseismic weight 35 and a piezoelement 36 being disposed in sleeve 34.Piezoelement 36 comprises three crystal discs 37 with electrodes 38,39therebetween. A central passage 23 extends through the integers 33 and37-39 and is adapted to receive the cable plug. in just the same way asin the embodiment shown in FIG. 2,

spring sleeves 24 or the like are inserted in passage 23 and providedirect electrical contact between the cable contact members 8,9 and theelectrodes 38,39 and between the cable sheath 5 and the baseplate 33,which serves as an earthing connection. Sealing-tightness and, whereapplicable, location of cable 1 is provided by an O-ring 31. In thisembodiment, therefore, the cable plug is inserted directly in thepick-up i.e., the piezoelement 36 -'and so no separate connecting socketor box is required.

I claim:

1. A cable connector assembly adapted for use in completing connectionto equipment or interconnecting electric cables having a'pair ofconductors embedded in an inorganic insulating material enclosed by ametal tube, said assembly comprising:

cable plug means including,

a first cylindrical insulator of main body diameter less than that ofthe cable metal tube outer diameter and having one end of reduceddiameter that is fittingly received within said cable metal tube withthe cable conductors passing through longitudinally extending openingsin said insulator,

a hollow cylindrical metal tube of outer diameter substantiallyidentical to that of the cable tube fittingly received onto a reduceddiameter end portion of said first insulator, one of said cableconductors being connected to said metal tube at an interior surface,

a second cylindrical insulator having an end of reduced diameterfittingly received within the hollow cylindrical metal tube and spacedfrom the first insulator end portion, said second insulator having amain body diameter not more than the outer diameter of said hollowcylindrical metal tube, said second insulator being provided with anopening extending longitudinally thereof through which the other cableconductor passes, and

a cylindrical metal cap of diameter substantially identical with that ofthe cable metal tube having an open end received onto a reduced diameterportion of the other end of said second insulator and a closed end wallwith an axially extending opening through which the other cableconductor extends for securement to the metal cap on its outer surface,

said reduced diameter end portions of said first and second insulatorsbeing metallized and bodies of brazing means interconnecting saidmetallized end portions and the cable tube, hollow cylindrical metaltube and cylindrical metal cap, respectively, hermetically sealing theinterior of said plug means; and

socket means for receiving therewithin said cable plug means and the endportion of the cable tube received onto said first insulator including,

individual contact means for the cable tube, hollow cylindrical metaltube and metal cap arranged in mutually spaced relation and having acommon opening therethrough through which said plug means and cable tubepasses,

insulating discs separating the contact means, and

individual spring means resiliently electrically interconnecting thecable tube, hollow cylindrical metal tube and metal cap to therespective contact means.

2. A cable connector assembly as in claim 1, wherein the common passageprovided in the contact elements of the socket extends through theinsulating discs and is smaller in diameter than the outside diameter ofthe spring means.

3. A cable connector assembly adapted for completing connection toequipment or interconnecting electric cables having a pair of conductorsembedded in an inorganic insulating material enclosed by a cylindricalmetal sheath, said assembly comprising:

cable plug means including,

a first cylindrical insulator of main body diameter less than that ofthe cable metal sheath outer diameter and having one end fittinglyreceived within said cable sheath with the cable conductors passingthrough respective longitudinally extending openings in said insulator,

a hollow cylindrical metal tube of outer diameter substantiallyidentical to that of the cable tube received onto the other end portionof said first insulator, one of said cable conductors being connected tosaid metal tube at an interior surface thereof,

a second cylindrical insulator having an end received within the hollowcylindrical metal tube and spaced from the first insulator end portion,said second insulator having a main body diameter not greater than theouter diameter of said hollow cylindrical metal tube and said secondinsulator being provided with an opening extending longitudinallythereof through which the other cable conductor passes, and

a cylindrical metal cap of diameter substantially identical and nogreater than that of the cable metal sheath having an open end receivedonto the other end portion of said second insulator and a closed endwall with an axially extending.

opening through which the other cable conductor extends for securementto the metal cap,

said end portions of said first and second insulators being metallizedand bodies of brazing means interconnecting said metallized end portionsand the cable tube, hollow cylindrical metal tube and cylindrical metalcap, respectively, thereby hermetically sealing the interior of saidplug means; and

socket means for receiving therewithin said cable plug means and the endportion of the cable sheath received onto said first insulatorincluding,

individual contact means for the cable sheath, hollow cylindrical metaltube and metal cap arranged in mutually spaced relation and having acommon opening through which said plug means and cable sheath passes,

insulating discs separating the contact means, and

individual spring means resiliently electrically interconnecting thecable sheath, hollow cylindrical metal tube and metal cap to therespective contact means.

4. A cable connector assembly adapted to be used for connecting toequipment or interconnecting minerally insulated electric cables havingtwo conductors embedded in an inorganic insulating material enclosed bya metal tube, said assembly comprising:

a cable plug disposed at the cable end and a socket adapted to receivethe cable plug;

the cable plug being composed of two tubular contact members connectedto the cable conductors and of two substantially cylindrical insulatorsof ceramic material electrically insulating the contact members from oneanother, the outside diameters of the contact members and of theinsulators corresponding at least substantially to the metal tube sizeof the cable, the two tubular contact members and the insulators beingdisposed in consecutive aligned relationship so that the first insulatorfollows the metal tube, the first contact member being disposed betweenand engaging at both ends thereof over the two insulators and the secondcontact member being engaged like a cap on the outside end of the secondinsulator, the insulators being metallized on their surfaces in contactwith the metal tube and with the contact members and being hermeticallysecured thereto by brazing; and

the socket including at least two consecutive contact elements providedwith at least one common passage extending therethrough and insulatingdiscs separating the contact elements from one another, spring meansbeing inserted into the contact elements and cooperating with thecontact members of the cable plug which is adapted to be plugged intothe common passage in the contact elements of the socket.

5. A cable connector assembly adapted to be used for connecting toequipment or interconnecting minerally insulated electric cables havingtwo conductors embedded in an inorganic insulating material enclosed bya metal tube, said assembly comprising:

a cable plug disposed at the cable end and a socket adapted to receivethe cable plug;

the cable plug being composed of two tubular contact members connectedto the cable conductors and of two substantially cylindrical insulatorsof ceramic material electrically insulating the contact members from oneanother, the outside diameters v of the contact members and of theinsulators corresponding at least substantially to the metal tube sizeof the cable, the two tubular contact members and the insulators beingdisposed in consecutive aligned relationship so that the first insulatorfollows the metal tube, the first contact member being disposed betweenand engaging at both ends thereof over the two insulators and the secondcontact member being engaged like a cap on the outside end of the secondinsulator, the insulators being metallized on their surfaces in contactwith the metal tube and with the contact members and being hermeticallysecured thereto by brazing; and

the socket including at least two consecutive contact elements providedwith at least one common passage extending therethrough and insulatingdiscs separating the contact elements from one another, spring meansbeing inserted into the contact elements and cooperating with thecontact members of the cable plug which is adapted to be plugged intothe common passage in the contact elements of the socket, said socketfurther including a piezoelectric signal generator having piezoelectriccrystal discs separated by electrodes, the electrodes forming thecontact elements and the crystal discs of the signal generator formingthe insulating discs of the socket.

diameter below that of the surfaces with which they contact the metaltube of the cable and the contact members.

8. A cable connector assembly as claimed in claim 3, wherein the commonpassage provided in the contact elements of the socket extends throughthe insulating discs and is smaller in diameter than the outsidediameter of the spring means inserted into the contact elements.

UNlTED STATES PATENT O'FFICE CERTIFICATE OF CORRECTION 3,772,545 DatedNovember 13, 1973 Rudolf A. Hat schek. I

"Patent No.

"I nv entor(s) I It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 2 line 156; delete the period (J after "'outside". Column 4,line. 11, "axil" should read axial Column 9, lin 3 ,f'[thre'ugh"' shouldread through Signed 'ar ld sealed this 24th day of September 1974'.

(SEAL) Attest: McCOY M..'GIB'SON JR. 0. MARSHALL DANN V AttestingOfficer v Commissioner of Patents uscoMM-oc scan- UNITED STATES PATENTOFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,772 ,545 Dated November13, 1973 Rudolf A. Hatschek Inventor(s) It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

Column 2, line 36, delete the period after "outside"; Column 4 line 11,"axil" should read axial Column 9, line 3,"?thrugh" should read throughSigned; and sealed this 24th day of September 1974 (SEAL) Attest:

McCOY M. 361350: JR. I c. MARSHALL DANN. Attesting Officer Commissionerof Patents 7 FORM, po-ioso (10-69)

1. A cable connector assembly adapted for use in completing connectionto equipment or interconnecting electric cables having a pair ofconductors embedded in an inorganic insulating material enclosed by ametal tube, said assembly comprising: cable plug means including, afirst cylindrical insulator of main body diameter less than that of thecable metal tube outer diameter and having one end of reduced diameterthat is fittingly received within said cable metal tube with the cableconductors passing through longitudinally extending openings in saidinsulator, a hollow cylindrical metal tube of outer diametersubstantially identical to that of the cable tube fittingly receivedonto a reduced diameter end portion of said first insulator, one of saidcable conductors being connected to said metal tube at an interiorsurface, a second cylindrical insulator having an End of reduceddiameter fittingly received within the hollow cylindrical metal tube andspaced from the first insulator end portion, said second insulatorhaving a main body diameter not more than the outer diameter of saidhollow cylindrical metal tube, said second insulator being provided withan opening extending longitudinally thereof through which the othercable conductor passes, and a cylindrical metal cap of diametersubstantially identical with that of the cable metal tube having an openend received onto a reduced diameter portion of the other end of saidsecond insulator and a closed end wall with an axially extending openingthrough which the other cable conductor extends for securement to themetal cap on its outer surface, said reduced diameter end portions ofsaid first and second insulators being metallized and bodies of brazingmeans interconnecting said metallized end portions and the cable tube,hollow cylindrical metal tube and cylindrical metal cap, respectively,hermetically sealing the interior of said plug means; and socket meansfor receiving therewithin said cable plug means and the end portion ofthe cable tube received onto said first insulator including, individualcontact means for the cable tube, hollow cylindrical metal tube andmetal cap arranged in mutually spaced relation and having a commonopening therethrough through which said plug means and cable tubepasses, insulating discs separating the contact means, and individualspring means resiliently electrically interconnecting the cable tube,hollow cylindrical metal tube and metal cap to the respective contactmeans.
 2. A cable connector assembly as in claim 1, wherein the commonpassage provided in the contact elements of the socket extends throughthe insulating discs and is smaller in diameter than the outsidediameter of the spring means.
 3. A cable connector assembly adapted forcompleting connection to equipment or interconnecting electric cableshaving a pair of conductors embedded in an inorganic insulating materialenclosed by a cylindrical metal sheath, said assembly comprising: cableplug means including, a first cylindrical insulator of main bodydiameter less than that of the cable metal sheath outer diameter andhaving one end fittingly received within said cable sheath with thecable conductors passing through respective longitudinally extendingopenings in said insulator, a hollow cylindrical metal tube of outerdiameter substantially identical to that of the cable tube received ontothe other end portion of said first insulator, one of said cableconductors being connected to said metal tube at an interior surfacethereof, a second cylindrical insulator having an end received withinthe hollow cylindrical metal tube and spaced from the first insulatorend portion, said second insulator having a main body diameter notgreater than the outer diameter of said hollow cylindrical metal tubeand said second insulator being provided with an opening extendinglongitudinally thereof through which the other cable conductor passes,and a cylindrical metal cap of diameter substantially identical and nogreater than that of the cable metal sheath having an open end receivedonto the other end portion of said second insulator and a closed endwall with an axially extending opening through which the other cableconductor extends for securement to the metal cap, said end portions ofsaid first and second insulators being metallized and bodies of brazingmeans interconnecting said metallized end portions and the cable tube,hollow cylindrical metal tube and cylindrical metal cap, respectively,thereby hermetically sealing the interior of said plug means; and socketmeans for receiving therewithin said cable plug means and the endportion of the cable sheath received onto said first insulatorincluding, individual contact means for the cable sheath, hollowcylindrical metal tube and metal cap arranged in mutually sPacedrelation and having a common opening through which said plug means andcable sheath passes, insulating discs separating the contact means, andindividual spring means resiliently electrically interconnecting thecable sheath, hollow cylindrical metal tube and metal cap to therespective contact means.
 4. A cable connector assembly adapted to beused for connecting to equipment or interconnecting minerally insulatedelectric cables having two conductors embedded in an inorganicinsulating material enclosed by a metal tube, said assembly comprising:a cable plug disposed at the cable end and a socket adapted to receivethe cable plug; the cable plug being composed of two tubular contactmembers connected to the cable conductors and of two substantiallycylindrical insulators of ceramic material electrically insulating thecontact members from one another, the outside diameters of the contactmembers and of the insulators corresponding at least substantially tothe metal tube size of the cable, the two tubular contact members andthe insulators being disposed in consecutive aligned relationship sothat the first insulator follows the metal tube, the first contactmember being disposed between and engaging at both ends thereof over thetwo insulators and the second contact member being engaged like a cap onthe outside end of the second insulator, the insulators being metallizedon their surfaces in contact with the metal tube and with the contactmembers and being hermetically secured thereto by brazing; and thesocket including at least two consecutive contact elements provided withat least one common passage extending therethrough and insulating discsseparating the contact elements from one another, spring means beinginserted into the contact elements and cooperating with the contactmembers of the cable plug which is adapted to be plugged into the commonpassage in the contact elements of the socket.
 5. A cable connectorassembly adapted to be used for connecting to equipment orinterconnecting minerally insulated electric cables having twoconductors embedded in an inorganic insulating material enclosed by ametal tube, said assembly comprising: a cable plug disposed at the cableend and a socket adapted to receive the cable plug; the cable plug beingcomposed of two tubular contact members connected to the cableconductors and of two substantially cylindrical insulators of ceramicmaterial electrically insulating the contact members from one another,the outside diameters of the contact members and of the insulatorscorresponding at least substantially to the metal tube size of thecable, the two tubular contact members and the insulators being disposedin consecutive aligned relationship so that the first insulator followsthe metal tube, the first contact member being disposed between andengaging at both ends thereof over the two insulators and the secondcontact member being engaged like a cap on the outside end of the secondinsulator, the insulators being metallized on their surfaces in contactwith the metal tube and with the contact members and being hermeticallysecured thereto by brazing; and the socket including at least twoconsecutive contact elements provided with at least one common passageextending therethrough and insulating discs separating the contactelements from one another, spring means being inserted into the contactelements and cooperating with the contact members of the cable plugwhich is adapted to be plugged into the common passage in the contactelements of the socket, said socket further including a piezoelectricsignal generator having piezoelectric crystal discs separated byelectrodes, the electrodes forming the contact elements and the crystaldiscs of the signal generator forming the insulating discs of thesocket.
 6. A cable connector assembly as claimed in claim 3, wherein theinsulators of the cable plug are formed with axial passages threughwhich the cable conductors extend, one conductor being secured to aplace on the inside surface of the contact member between the twoinsulators, the other conductor extending through a central passage ofthe cap-like end contact member and being hermetically secured to theoutside thereof by brazing or welding.
 7. A cable connector assembly asclaimed in claim 3, wherein the insulators of the cable plug are reducedin diameter below that of the surfaces with which they contact the metaltube of the cable and the contact members.
 8. A cable connector assemblyas claimed in claim 3, wherein the common passage provided in thecontact elements of the socket extends through the insulating discs andis smaller in diameter than the outside diameter of the spring meansinserted into the contact elements.